Let $\backslash$Pi $=($Gen$,$ Enc, Dec$)$ be a secret key EAV$-$secure encryption scheme, with message space M $=\{0,1\}^$n$.$ We design the scheme$\backslash$Pi $=($Gen$,$ Enc$,$ Dec$)$ as follows:

$$ Gen$=$Gen

$$ Enc$($k$,$ m$)$ :

$$ t $\{0,1\}^$n $($random sampling operation$)$

$$ c $$ Enc$($k$,$ t$)$

$$ return $($c$,$ t $$ m$)$

$$ Dec$($k$,$ ct$)$ :

$$ parse ct as $($c$,$ y$)$

$\backslash$alpha $$ Dec$($k$,$ c$)$

$$ return y $\backslash$alpha

Prove that $\backslash$Pi $$is EAV$-$secure$.$